stcd2400 STMicroelectronics, stcd2400 Datasheet - Page 17

• Manufacturer Part Number: stcd2400
• Description: Multichannel Clock Distribution Circuit
• Manufacturer: STMicroelectronics

STCD22x0, STCD23x0, STCD24x0
4.8
Typical application connections
The STCD2400 clock distribution circuit requires a source clock input as the reference clock
(for example, XO). At most 4 devices can be connected to the outputs. The typical
application circuit using STCD2400 is shown in
output and active low. A pull-up resistor is needed to connect to an external 1.8 V supply
VIO. If the clock source enable is active high, the user can use VTCXO as the master clock
enable control signal, please refer to
In
GSM transceiver separately to be used as reference clocks.
In
power consumption, a Bluetooth system always has a clock request feature. If the Bluetooth
system does not require the clock, the clock request disables the clock output. The enable
pins can also be connected to an external 1.8 V supply to force the buffer to always be on.
In
are connected to V
Figure 9.
Figure
Figure
Figure 9
C
9, the clock from XO is distributed to the TD-SCDMA transmitter and receiver and
10, the buffer #4 output is fed into the Bluetooth system. In order to allow minimum
and 10, all the output clock enables are active high since both OPT1 and OPT2
C
Typical application circuit using STCD24x0 for RF ends of TD-
SCDMA/GSM dual-mode mobile phone
XO
V
DD
CC
EN
.
VIO
C
V
CC
Doc ID 15400 Rev 2
OPT2
OPT1
VTCXO
MC
MCLK
BYP
REQ
STCD24x0
Figure 4
GND
V
CC
for the detailed connection.
CLK3
CLK1
CLK4
CLK2
EN2
EN4
EN3
EN1
Figure 9
Selection
and
Mode
10
. The MC
TD-SCDMA
Application information
Receiver
Transceiver
TD-SCDMA
Transmitter
GSM
REQ
is open drain
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